Process for determining the composition of copper and zinc alloys



July 10, 1928. 1,676,709

M. POLANYI ET AL PROCESS FOR DETERMINING THE COMPOSITION OF COPPER AND ZINC ALLOYS Filed Feb. 25, 1927 Jnden *0 rs Patented July 10, 1928.

UNITED STATES A 1,676,709 PATENT OFFICE.

MICHAEL POLANYI, OF BERLIN-ZEHLENDORF MITTE, AND STEPHAN voN BOGDANDY,

' 02F BERLIN-DAHLEM, GERMANY.

PROCESS FOR DETERMINING THF COMPOSITION OF COPPER AND ZINC ALLOYS.

Application fi1ed February 25, 1927, Serial No. 171,011, and in Germany March 24, 1926.

Our invention has for its object to pro-.

' are melted together for obtaining brass,

there is always a danger of the zinc oxidizing in the presence of air and accordingly escaping from the alloy. For this reason it is impossible to say beforehand what the exact composition of the alloy will be. In this case it is absolutely impossible to apply chemical analysis, as during the melting process the time. is too short to analyze the composition chemically and to make up possible losses of zinc by adding new metal.

Bv means of the present process these drawbacks are eliminated.

The process consists in heating, the brass or other alloy to be examinedin the form of drillings, powder, millings, grains and the like in a vessel of quartz glass, glass with a very high fusing point, zircon, iron or the like in as high a vacuum as possible to such anextent that the zinc passes off by distillation, the copper and the like remaining behind. By weighing the metal thus treated before and after heating to a point where no further changes. of weight take place the amount of zinc present is determined.

In the accompanying drawing a device suitable for this process is shown, by way of example, in diagrammatical manner.

a is a furnace, an electric furnace, for instance. I

A vessel 0 which is almost cylindrical, 0

preferably slightly tapered upwardly. is

' considerably reduced indiarneter. at b. This vessel is connected by means of metal, linings or sleeves d to a high vacuum tube 6. The linings or sleeves d are preferably provided with a cooling system 7, to allow cooling water to flow through. A weighing glass 9 containing the metal to be examined is introduced by means of a hook, for instance, or the like into the reduced portion 12 of the vessel 0. and after connecting the latter to the vacuum pipe 6, heating takes place in the heater 0 until the weight remains'constant. The heating is shown to be an' electrical heating, the proper heating degree is adjusted by means of a resistance coil (2 and an amperage indicator a The heater a is also connected to the cooling system by means of the pipes h, h. The vacuum required is produced by means of a mercury pump or the like, which is also connected to the cooling system by means of pipes 70, k and may also be connected by means of pipe Z, to a device or system not especially shown and adapted to produce a prior degree of vacuum. Within tube e we have provided a closing device such as cock m, an air entrance pipe n, and a vacuum measuring device 0 of any approved structure. The distilled zinc is condensed in that part of the vessel 0 next the sleeve. A portion may also be condensed at a point higher up, at 6. Should it be desired to recover the zinc quantitatively and thus prove the correctness of the analysis, a plug of asbestus, glassjor even wool or the like can be introduced into the receptacle 0 at 0 after cooling, and after analysis weighing may be performed. or, after dissolving, a titration or any other analytic means for determining .may be restored to. The heating at a takes place in accordance with the degree of volatility of the metal treated. As a rule a temperature is used ranging from 800to 1100.

In place of an electric heater a gas or alcohol lamp or the like may also be used.

The vessel 9 may also be of quartz glass or other substance or metal of sufliciently refractory nature.

The possibility .of zinc volatizing so rapidly from alloys of copper and zinc is surprising. It could not be anticipated that such large quantities would escape within such a short space of time. On the con trary, it was not unreasonable to expect that part of the metal would be retained. Our new method proved quite successful for all practical purposes.

What we claim as our invention and desire to secure by Letters Patent of the United States, is

1. A rocess for determining the composition o alloys of copper and zinc, consisting in Weighing a portion of the alloy to be treated, subjecting said weighed portion Ill of heat in a vacuum, maintaining said heat between 900 and 1100 until all the zinc contained in said alloy is volatilized, and 10 weighing the remaining metal.

MICHAEL POLANYI. STEPHAN YON BOGDANDY. 

